Upload the texture via PBOs. Slight speedup on nVidia, rather neutral on Intel.

[movit] / effect_chain.cpp

diff --git a/effect_chain.cpp b/effect_chain.cpp
index a90f5f3a64db0ffea0427cc009fc106c56eebf0a..9eee1f66faaf1622715002d44edd195708cfc9fc 100644 (file)
--- a/effect_chain.cpp
+++ b/effect_chain.cpp
@@ -185,21 +185,8 @@ void EffectChain::finalize()
        glLinkProgram(glsl_program_num);
        check_error();
 
-       finalized = true;
-}
-
-void EffectChain::render_to_screen(unsigned char *src)
-{
-       assert(finalized);
-
-       check_error();
-       glUseProgram(glsl_program_num);
-       check_error();
-
-       glActiveTexture(GL_TEXTURE0);
-       glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
-
-       GLenum format, internal_format;
+       // Translate the format to OpenGL's enums.
+       GLenum internal_format;
        if (use_srgb_texture_format) {
                internal_format = GL_SRGB8;
        } else {
@@ -207,22 +194,65 @@ void EffectChain::render_to_screen(unsigned char *src)
        }
        if (input_format.pixel_format == FORMAT_RGB) {
                format = GL_RGB;
+               bytes_per_pixel = 3;
        } else if (input_format.pixel_format == FORMAT_RGBA) {
                format = GL_RGBA;
+               bytes_per_pixel = 4;
        } else if (input_format.pixel_format == FORMAT_BGR) {
                format = GL_BGR;
+               bytes_per_pixel = 3;
        } else if (input_format.pixel_format == FORMAT_BGRA) {
                format = GL_BGRA;
+               bytes_per_pixel = 4;
        } else {
                assert(false);
        }
 
-       static bool first = true;
-       if (first) {
-               glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, GL_UNSIGNED_BYTE, src);
-       } else {
-               glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, format, GL_UNSIGNED_BYTE, src);
-       }
+       // Create PBO to hold the texture, and then the texture itself.
+       glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 2);
+       check_error();
+       glBufferData(GL_PIXEL_UNPACK_BUFFER_ARB, width * height * bytes_per_pixel, NULL, GL_STREAM_DRAW);
+       check_error();
+
+       void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
+       memset(mapped_pbo, 0, width * height * bytes_per_pixel);
+       glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
+       
+       glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
+       check_error();
+       glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
+       check_error();
+       glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
+       check_error();
+
+       finalized = true;
+}
+
+void EffectChain::render_to_screen(unsigned char *src)
+{
+       assert(finalized);
+
+       // Copy the pixel data into the PBO.
+       glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 2);
+       check_error();
+       void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
+       memcpy(mapped_pbo, src, width * height * bytes_per_pixel);
+       glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
+       check_error();
+
+       // Re-upload the texture from the PBO.
+       glActiveTexture(GL_TEXTURE0);
+       check_error();
+       glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
+       check_error();
+       glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, format, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
+       check_error();
+       glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
+       check_error();
+
+       glUseProgram(glsl_program_num);
+       check_error();
+
        check_error();
        glUniform1i(glGetUniformLocation(glsl_program_num, "input_tex"), 0);